There are several advantages of photovoltaic solar power that make it one of the most promising renewable energy sources in the world. The photovoltaic solar power is free, needs no fuel and produces no waste or pollution, and the solar power generator requires little maintenance and no supervision and has a life of 20-30 years with low running costs. Solar power generators are simply distributed to homes, schools, or businesses, where their assemblies require no extra development or land area and their functions are safe and quiet. Remote areas can easily produce their own supply of electricity by constructing as small or as large of a system as needed.
Generally, the solar or photovoltaic module for generating electric energy from sunlight comprises a plurality of solar or photovoltaic cells. The solar cells in a solar module are usually connected to each other by thin conductor strips (i.e. conductor ribbons). These thin conductor strips are routed out of the solar module on the side facing away from the sun. The thin conductor strips are mostly made of copper foils and protruded from the rear side of the solar module (i.e. solar panel). These flexible and thin conductor strips are very sensitive and difficult to contact. Therefore, one or more junction boxes are employed for the solar module and thin conductor strips are manually contacted with electrical terminal receptacles of the junction box. In addition, the junction box is an integral part of a solar or photovoltaic system and it provides electrical connections between the solar cells of the individual solar module (i.e. solar panel) and between the solar modules and other components of the system (i.e. DC/AC inverter). Generally, the junction box is disposed on a rear surface of the solar panel and has electrical connection mechanism in the interior for contacting the thin conductor strips of the solar modules and conducting the electrical current generated by the solar modules to the outside. Without a junction box, the solar modules could not work properly.
Generally, plural solar modules are operated in series connection, wherein a so called bypass diode is anti-parallel connected to each solar module. The bypass diode is disposed inside the junction box and fastened and connected to the electrical connection mechanism of the junction box. In a case of a solar module is shaded or does not produce electricity because of defect, this solar module would lower the power of the solar modules in series connection or even suffers damage without bypass diode. This is because that if a solar cell within a solar cell group of the solar module is partially shaded, this shaded solar cell acts as a blocking diode or resistor within the circuit of the solar cell group, which may result in a damage of the shaded solar cell and result in the entire solar cell group of the solar module no longer being able to supply electric energy. The above-mentioned situations can be avoided by using the bypass diode of the junction box, because the current flows through the diode and is sustained. In other words, the bypass diodes are electrically connected in an anti-parallel manner with respect to the solar cell groups and have the effect that the current flow through the solar module is led past solar cell groups that only supply low power, i.e. the terminals of this solar cell group of a solar module are short-circuited by the bypass diode and the corresponding cell group is bypassed thereby. Thus, such a solar cell group does no longer contribute to the overall performance of the solar module, but the overall current flow through the solar panel is substantially unobstructed and a damage of individual solar cell is avoided.
It is obviously that due to the mechanical conditions particularly the form of the thin conductor strips and the bypass diodes, a number of difficulties occur when constructing the junction box. In addition, due to the manual connecting, the assembly and installation of the thin conductor strips and the bypass diodes with the electrical connection mechanism inside the junction box is cost and laborious. Furthermore, when one of the bypass diodes is breakdown, it is difficult to check which one is failed and laborious to replace the failed bypass diode with a new one. Up to now, the conventional junction box is complex in construction and installing the junction box is laborious. In addition, the conventional junction box doesn't provide reliable electrical connections and the durability of the junction box is low. It is therefore desirable to provide a junction box that is simple in structure, cost-effective, durable enough to withstand a wide range of environment conditions and easily be installed and maintained, while maintaining a high-quality, reliable electrical connections between the components of a solar or photovoltaic system.